The mass and energy balance of ice within the Eisriesenwelt cave, Austria

Abstract

Abstract. Meteorological and glaciological measurements were performed in a prominent ice cave (Eisriesenwelt, Austria) during a full annual cycle. The observed meteorological conditions feature the basic characteristics of a dynamically ventilated cave system with a well distinguished winter and summer regime. The calculated energy balance of the ice is largely predetermined by the input of long-wave radiation originating at the host rock surface. On average the turbulent fluxes withdraw energy from the surface. This is more pronounced during winter due to enhanced circulation and lower humidity. During summer the driving gradients reverse sign and the associated fluxes provide some energy for melt. About 4 cm of ice were lost at the measurements site during a reference year. This was due to some sublimation during winter, while the major loss resulted from melt during summer. Small amounts of accumulation occurred during spring due to refreezing of seepage water. These results are largely based on employing a numerical mass and energy balance model. Sensitivity studies prove their reliability regarding diverse measurement uncertainties and indicate that the annual mass balance essentially depends on summer temperature and the availability of seepage water in spring. The latter induces a considerable interannual and spatial variability of the mass budget.